In the thick film fabrication of elements such as electrical resistors on circuit boards, it is important that the finished resistor have accurately controlled dimensions so that its resistance be made to correspond to a predetermined value. In prior art thick film screens, it has been common to use a woven screen with a mesh as fine as 400 wires per inch and to either immerse the screen in a photosensitive emulsion which is photo chemically developed to provide the resistor pattern or to apply a foil to one surface of the woven screen to define the pattern for the thick film elements. In either case it has been necessary to trim the resulting thick film elements so that, in the case of resistors, accurate resistance values can be achieved.
The inaccuracies in these prior art techniques are due in part to a lack of control over the cross sections of the resulting thick film elements. Particularly in the case of the emulsion filled weave, a thick deposition is difficult to achieve and thickness control is poor. In the case of the foil technique, while cross-sectional control is improved, it is difficult to achieve islands in the thick film deposition.